在 TikZ/PGF 中创建“有底部的圆柱体”节点形状

Question

如何创建自定义 TikZ 节点“有底部的圆柱体”，其中圆柱体底部的隐藏线使用虚线显示。

类似于下面的创作，除了节点中心应该在圆柱体的中间（好像它位于 3D 圆柱体的中心），而不是在侧面的中心 - 它看起来不平衡

https://www.writelatex.com/1149537sksqzs#/2737083/

\documentclass[tikz]{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes.geometric,calc}

\begin{document}
\begin{tikzpicture}
  \node[cylinder,draw=black,thick,aspect=0.7,
        minimum height=1.7cm,minimum width=1.5cm,
        shape border rotate=90,
        cylinder uses custom fill,
        cylinder body fill=red!30,
        cylinder end  fill=red!10]
   (A) {A};
  \draw[dashed]
    let \p1 = ($ (A.after bottom) - (A.before bottom) $),
        \n1 = {0.5*veclen(\x1,\y1)},
        \p2 = ($ (A.bottom) - (A.after bottom)!.5!(A.before bottom) $),
        \n2 = {veclen(\x2,\y2)}
  in
    (A.before bottom) arc [start angle=0, end angle=180,
    x radius=\n1, y radius=\n2];
\end{tikzpicture}
\end{document}

Answer 1

Tarass 猜对了，这是线宽的问题，但它既影响圆弧半径，又影响初始点(A.before bottom)。以下是可能的解决方法：

\documentclass[tikz]{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes.geometric,calc}

\title{TikZ: cylinder with bottom - example}
\begin{document}
\begin{tikzpicture}
  \node[cylinder,draw=black,thick,aspect=0.7,minimum height=1.7cm,minimum width=1.5cm,shape border rotate=90,cylinder uses custom fill, cylinder body fill=red!30,cylinder end fill=red!10] (A) {A};
  \draw[dashed]
    let \p1 = ($ (A.after bottom) - (A.before bottom) $),
        \n1 = {0.5*veclen(\x1,\y1)-\pgflinewidth},
        \p2 = ($ (A.bottom) - (A.after bottom)!.5!(A.before bottom) $),
        \n2 = {veclen(\x2,\y2)-\pgflinewidth}
  in
    ([xshift=-\pgflinewidth] A.before bottom) arc [start angle=0, end angle=180,
    x radius=\n1, y radius=\n2];
\end{tikzpicture}
\end{document}